ChildLink(mapping=None, *, ignore_unknown_fields=False, **kwargs)Metadata associated with a parent-child relationship appearing in a
PlanNode][google.spanner.v1.PlanNode].
Attributes | |
|---|---|
| Name | Description |
child_index |
int
The node to which the link points. |
type_ |
str
The type of the link. For example, in Hash Joins this could be used to distinguish between the build child and the probe child, or in the case of the child being an output variable, to represent the tag associated with the output variable. |
variable |
str
Only present if the child node is SCALAR][google.spanner.v1.PlanNode.Kind.SCALAR] and
corresponds to an output variable of the parent node. The
field carries the name of the output variable. For example,
a TableScan operator that reads rows from a table will
have child links to the SCALAR nodes representing the
output variables created for each column that is read by the
operator. The corresponding variable fields will be set
to the variable names assigned to the columns.
|